It had to happen eventually, replacement parts order from Vans required! Despite reading about a mistake a fellow 14 builder had made when dimpling the rearmost bulkhead, I managed to repeat the exact same error. There was a small note at the start of this sequence which said that all manufactured heads should be on the aft face of the bulkhead. It was only when I started to rivet the 2 bulkheads together that I realised that I had dimpled the wrong side. What a muppet as I had made a mental note when I had read the other builder’s blog. It could be worse as luckily these are small parts.
So, parts put aside I cracked on with the next few chapters which involve the other bulkheads and horizontal stabiliser mounts. These are fairly substantial parts with long 470-4 rivets. I used the C-Frame again for these with the back riveting attachment as squeezing them was not feasible. They worked out quite nicely.
All of the bulkhead riveting takes some careful reading (once bitten, twice…) as it is important to get the shop and manufactured heads on the right face for future clearance puposes.
Next up were the frame bulkheads that needed to be dimpled then joined together. The smaller of the two required a systems hole to be enlarged with the step drill and then the rudder cable guide riveted on once the two halves had been joined.
The next build is to attach the nut plates to the battery angles. This was easily achieved with the squeezer after having countersunk the angles.
Next, the battery angles are attached to the bellcrank ribs. Again, straightforward as the rivets can be set with the squeezer.
The forward bulkhead that handles all the connections is finished next. There are a lot of nutplates on this part and the dimpling is very specific. Paranoia had set in by this time and I even labelled the aft face to prevent further cock-ups. All of the nutplates could be set with the squeezer with a little manipulation of position and swapping the sets.
The bellcrank ribs are then attached to the systems bulkhead. I found the 470-4 rivets quite hard to set and they had to be hit with the gun. It is quite awkward to get the bucking bar in between the flanges of the bellcrank ribs. I did let the gun slip off the head on one of the rivets and made a small dent. I drilled the rivet out and with a combination of tungsten bucking bars and a soft hammer, I flattened the face and riveted it again. The top two rivets are flush as per the plans as something must sit against this face.
I was going to stop at this point and call it a day but I seemed to be on a roll so I carried on a connected the large bulkhead to the bellcrank ribs. I was pretty unsure as to which side the shop head of the rivets should go on so took the path of least resistance. I’m not sure that the preceding instruction to put the manufactured head on the forward face still applied to a new page although I have seen other builders try. I couldn’t see how to get the gun inside the flange to set the rivets with the shop head on the inside. It doesn’t seem that there is any structural reason for this and I’m not going to crawl down there to admire the view!
I stopped here for the day but had a quick read of what was next. The bottom skin needs to be dimpled but I require a reduced diameter female dimple die to fit in the J channel which I will order from Cleaveland tomorrow. When I was prepping the stiffeners I thought that they looked a little strange in terms of where the holes had been punched. It asks you to dimple the holes but they are directly in the channel and clearly impossible to get a die set anywhere near the hole.
I was reading another builder’s blog and he had the same issue. It turns out that the holes had actually been punched incorrectly, the holes should be in the flange and Vans had to send out replacements. Looks like I might get my new bulkheads with the replacement stiffeners! The power of the internet solves another mystery.
I love dimpling…